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MAINTAINERS: Add myself as maintainer to X86 machines
[qemu.git] / hw / block / xen_disk.c
blobf74fcd42d1ee5683b64db972a2ed8f15ba41725c
1 /*
2 * xen paravirt block device backend
3 *
4 * (c) Gerd Hoffmann <kraxel@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; under version 2 of the License.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, see <http://www.gnu.org/licenses/>.
17 *
18 * Contributions after 2012-01-13 are licensed under the terms of the
19 * GNU GPL, version 2 or (at your option) any later version.
20 */
21
22 #include "qemu/osdep.h"
23 #include <sys/ioctl.h>
24 #include <sys/uio.h>
25
26 #include "hw/hw.h"
27 #include "hw/xen/xen_backend.h"
28 #include "xen_blkif.h"
29 #include "sysemu/blockdev.h"
30 #include "sysemu/iothread.h"
31 #include "sysemu/block-backend.h"
32 #include "qapi/error.h"
33 #include "qapi/qmp/qdict.h"
34 #include "qapi/qmp/qstring.h"
35 #include "trace.h"
36
37 /* ------------------------------------------------------------- */
38
39 static int batch_maps = 0;
40
41 /* ------------------------------------------------------------- */
42
43 #define BLOCK_SIZE 512
44 #define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
45
46 struct PersistentGrant {
47 void *page;
48 struct XenBlkDev *blkdev;
49 };
50
51 typedef struct PersistentGrant PersistentGrant;
52
53 struct PersistentRegion {
54 void *addr;
55 int num;
56 };
57
58 typedef struct PersistentRegion PersistentRegion;
59
60 struct ioreq {
61 blkif_request_t req;
62 int16_t status;
63
64 /* parsed request */
65 off_t start;
66 QEMUIOVector v;
67 int presync;
68 uint8_t mapped;
69
70 /* grant mapping */
71 uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
72 uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
73 int prot;
74 void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
75 void *pages;
76 int num_unmap;
77
78 /* aio status */
79 int aio_inflight;
80 int aio_errors;
81
82 struct XenBlkDev *blkdev;
83 QLIST_ENTRY(ioreq) list;
84 BlockAcctCookie acct;
85 };
86
87 #define MAX_RING_PAGE_ORDER 4
88
89 struct XenBlkDev {
90 struct XenDevice xendev; /* must be first */
91 char *params;
92 char *mode;
93 char *type;
94 char *dev;
95 char *devtype;
96 bool directiosafe;
97 const char *fileproto;
98 const char *filename;
99 unsigned int ring_ref[1 << MAX_RING_PAGE_ORDER];
100 unsigned int nr_ring_ref;
101 void *sring;
102 int64_t file_blk;
103 int64_t file_size;
104 int protocol;
105 blkif_back_rings_t rings;
106 int more_work;
107 int cnt_map;
108
109 /* request lists */
110 QLIST_HEAD(inflight_head, ioreq) inflight;
111 QLIST_HEAD(finished_head, ioreq) finished;
112 QLIST_HEAD(freelist_head, ioreq) freelist;
113 int requests_total;
114 int requests_inflight;
115 int requests_finished;
116 unsigned int max_requests;
117
118 /* Persistent grants extension */
119 gboolean feature_discard;
120 gboolean feature_persistent;
121 GTree *persistent_gnts;
122 GSList *persistent_regions;
123 unsigned int persistent_gnt_count;
124 unsigned int max_grants;
125
126 /* qemu block driver */
127 DriveInfo *dinfo;
128 BlockBackend *blk;
129 QEMUBH *bh;
130
131 IOThread *iothread;
132 AioContext *ctx;
133 };
134
135 /* ------------------------------------------------------------- */
136
137 static void ioreq_reset(struct ioreq *ioreq)
138 {
139 memset(&ioreq->req, 0, sizeof(ioreq->req));
140 ioreq->status = 0;
141 ioreq->start = 0;
142 ioreq->presync = 0;
143 ioreq->mapped = 0;
144
145 memset(ioreq->domids, 0, sizeof(ioreq->domids));
146 memset(ioreq->refs, 0, sizeof(ioreq->refs));
147 ioreq->prot = 0;
148 memset(ioreq->page, 0, sizeof(ioreq->page));
149 ioreq->pages = NULL;
150
151 ioreq->aio_inflight = 0;
152 ioreq->aio_errors = 0;
153
154 ioreq->blkdev = NULL;
155 memset(&ioreq->list, 0, sizeof(ioreq->list));
156 memset(&ioreq->acct, 0, sizeof(ioreq->acct));
157
158 qemu_iovec_reset(&ioreq->v);
159 }
160
161 static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
162 {
163 uint ua = GPOINTER_TO_UINT(a);
164 uint ub = GPOINTER_TO_UINT(b);
165 return (ua > ub) - (ua < ub);
166 }
167
168 static void destroy_grant(gpointer pgnt)
169 {
170 PersistentGrant *grant = pgnt;
171 xengnttab_handle *gnt = grant->blkdev->xendev.gnttabdev;
172
173 if (xengnttab_unmap(gnt, grant->page, 1) != 0) {
174 xen_pv_printf(&grant->blkdev->xendev, 0,
175 "xengnttab_unmap failed: %s\n",
176 strerror(errno));
177 }
178 grant->blkdev->persistent_gnt_count--;
179 xen_pv_printf(&grant->blkdev->xendev, 3,
180 "unmapped grant %p\n", grant->page);
181 g_free(grant);
182 }
183
184 static void remove_persistent_region(gpointer data, gpointer dev)
185 {
186 PersistentRegion *region = data;
187 struct XenBlkDev *blkdev = dev;
188 xengnttab_handle *gnt = blkdev->xendev.gnttabdev;
189
190 if (xengnttab_unmap(gnt, region->addr, region->num) != 0) {
191 xen_pv_printf(&blkdev->xendev, 0,
192 "xengnttab_unmap region %p failed: %s\n",
193 region->addr, strerror(errno));
194 }
195 xen_pv_printf(&blkdev->xendev, 3,
196 "unmapped grant region %p with %d pages\n",
197 region->addr, region->num);
198 g_free(region);
199 }
200
201 static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
202 {
203 struct ioreq *ioreq = NULL;
204
205 if (QLIST_EMPTY(&blkdev->freelist)) {
206 if (blkdev->requests_total >= blkdev->max_requests) {
207 goto out;
208 }
209 /* allocate new struct */
210 ioreq = g_malloc0(sizeof(*ioreq));
211 ioreq->blkdev = blkdev;
212 blkdev->requests_total++;
213 qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST);
214 } else {
215 /* get one from freelist */
216 ioreq = QLIST_FIRST(&blkdev->freelist);
217 QLIST_REMOVE(ioreq, list);
218 }
219 QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list);
220 blkdev->requests_inflight++;
221
222 out:
223 return ioreq;
224 }
225
226 static void ioreq_finish(struct ioreq *ioreq)
227 {
228 struct XenBlkDev *blkdev = ioreq->blkdev;
229
230 QLIST_REMOVE(ioreq, list);
231 QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list);
232 blkdev->requests_inflight--;
233 blkdev->requests_finished++;
234 }
235
236 static void ioreq_release(struct ioreq *ioreq, bool finish)
237 {
238 struct XenBlkDev *blkdev = ioreq->blkdev;
239
240 QLIST_REMOVE(ioreq, list);
241 ioreq_reset(ioreq);
242 ioreq->blkdev = blkdev;
243 QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list);
244 if (finish) {
245 blkdev->requests_finished--;
246 } else {
247 blkdev->requests_inflight--;
248 }
249 }
250
251 /*
252 * translate request into iovec + start offset
253 * do sanity checks along the way
254 */
255 static int ioreq_parse(struct ioreq *ioreq)
256 {
257 struct XenBlkDev *blkdev = ioreq->blkdev;
258 uintptr_t mem;
259 size_t len;
260 int i;
261
262 xen_pv_printf(&blkdev->xendev, 3,
263 "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n",
264 ioreq->req.operation, ioreq->req.nr_segments,
265 ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
266 switch (ioreq->req.operation) {
267 case BLKIF_OP_READ:
268 ioreq->prot = PROT_WRITE; /* to memory */
269 break;
270 case BLKIF_OP_FLUSH_DISKCACHE:
271 ioreq->presync = 1;
272 if (!ioreq->req.nr_segments) {
273 return 0;
274 }
275 /* fall through */
276 case BLKIF_OP_WRITE:
277 ioreq->prot = PROT_READ; /* from memory */
278 break;
279 case BLKIF_OP_DISCARD:
280 return 0;
281 default:
282 xen_pv_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n",
283 ioreq->req.operation);
284 goto err;
285 };
286
287 if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') {
288 xen_pv_printf(&blkdev->xendev, 0, "error: write req for ro device\n");
289 goto err;
290 }
291
292 ioreq->start = ioreq->req.sector_number * blkdev->file_blk;
293 for (i = 0; i < ioreq->req.nr_segments; i++) {
294 if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
295 xen_pv_printf(&blkdev->xendev, 0, "error: nr_segments too big\n");
296 goto err;
297 }
298 if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) {
299 xen_pv_printf(&blkdev->xendev, 0, "error: first > last sector\n");
300 goto err;
301 }
302 if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) {
303 xen_pv_printf(&blkdev->xendev, 0, "error: page crossing\n");
304 goto err;
305 }
306
307 ioreq->domids[i] = blkdev->xendev.dom;
308 ioreq->refs[i] = ioreq->req.seg[i].gref;
309
310 mem = ioreq->req.seg[i].first_sect * blkdev->file_blk;
311 len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk;
312 qemu_iovec_add(&ioreq->v, (void*)mem, len);
313 }
314 if (ioreq->start + ioreq->v.size > blkdev->file_size) {
315 xen_pv_printf(&blkdev->xendev, 0, "error: access beyond end of file\n");
316 goto err;
317 }
318 return 0;
319
320 err:
321 ioreq->status = BLKIF_RSP_ERROR;
322 return -1;
323 }
324
325 static void ioreq_unmap(struct ioreq *ioreq)
326 {
327 xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
328 int i;
329
330 if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
331 return;
332 }
333 if (batch_maps) {
334 if (!ioreq->pages) {
335 return;
336 }
337 if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
338 xen_pv_printf(&ioreq->blkdev->xendev, 0,
339 "xengnttab_unmap failed: %s\n",
340 strerror(errno));
341 }
342 ioreq->blkdev->cnt_map -= ioreq->num_unmap;
343 ioreq->pages = NULL;
344 } else {
345 for (i = 0; i < ioreq->num_unmap; i++) {
346 if (!ioreq->page[i]) {
347 continue;
348 }
349 if (xengnttab_unmap(gnt, ioreq->page[i], 1) != 0) {
350 xen_pv_printf(&ioreq->blkdev->xendev, 0,
351 "xengnttab_unmap failed: %s\n",
352 strerror(errno));
353 }
354 ioreq->blkdev->cnt_map--;
355 ioreq->page[i] = NULL;
356 }
357 }
358 ioreq->mapped = 0;
359 }
360
361 static int ioreq_map(struct ioreq *ioreq)
362 {
363 xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
364 uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
365 uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
366 void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
367 int i, j, new_maps = 0;
368 PersistentGrant *grant;
369 PersistentRegion *region;
370 /* domids and refs variables will contain the information necessary
371 * to map the grants that are needed to fulfill this request.
372 *
373 * After mapping the needed grants, the page array will contain the
374 * memory address of each granted page in the order specified in ioreq
375 * (disregarding if it's a persistent grant or not).
376 */
377
378 if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
379 return 0;
380 }
381 if (ioreq->blkdev->feature_persistent) {
382 for (i = 0; i < ioreq->v.niov; i++) {
383 grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
384 GUINT_TO_POINTER(ioreq->refs[i]));
385
386 if (grant != NULL) {
387 page[i] = grant->page;
388 xen_pv_printf(&ioreq->blkdev->xendev, 3,
389 "using persistent-grant %" PRIu32 "\n",
390 ioreq->refs[i]);
391 } else {
392 /* Add the grant to the list of grants that
393 * should be mapped
394 */
395 domids[new_maps] = ioreq->domids[i];
396 refs[new_maps] = ioreq->refs[i];
397 page[i] = NULL;
398 new_maps++;
399 }
400 }
401 /* Set the protection to RW, since grants may be reused later
402 * with a different protection than the one needed for this request
403 */
404 ioreq->prot = PROT_WRITE | PROT_READ;
405 } else {
406 /* All grants in the request should be mapped */
407 memcpy(refs, ioreq->refs, sizeof(refs));
408 memcpy(domids, ioreq->domids, sizeof(domids));
409 memset(page, 0, sizeof(page));
410 new_maps = ioreq->v.niov;
411 }
412
413 if (batch_maps && new_maps) {
414 ioreq->pages = xengnttab_map_grant_refs
415 (gnt, new_maps, domids, refs, ioreq->prot);
416 if (ioreq->pages == NULL) {
417 xen_pv_printf(&ioreq->blkdev->xendev, 0,
418 "can't map %d grant refs (%s, %d maps)\n",
419 new_maps, strerror(errno), ioreq->blkdev->cnt_map);
420 return -1;
421 }
422 for (i = 0, j = 0; i < ioreq->v.niov; i++) {
423 if (page[i] == NULL) {
424 page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
425 }
426 }
427 ioreq->blkdev->cnt_map += new_maps;
428 } else if (new_maps) {
429 for (i = 0; i < new_maps; i++) {
430 ioreq->page[i] = xengnttab_map_grant_ref
431 (gnt, domids[i], refs[i], ioreq->prot);
432 if (ioreq->page[i] == NULL) {
433 xen_pv_printf(&ioreq->blkdev->xendev, 0,
434 "can't map grant ref %d (%s, %d maps)\n",
435 refs[i], strerror(errno), ioreq->blkdev->cnt_map);
436 ioreq->mapped = 1;
437 ioreq_unmap(ioreq);
438 return -1;
439 }
440 ioreq->blkdev->cnt_map++;
441 }
442 for (i = 0, j = 0; i < ioreq->v.niov; i++) {
443 if (page[i] == NULL) {
444 page[i] = ioreq->page[j++];
445 }
446 }
447 }
448 if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
449 (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
450 ioreq->blkdev->max_grants))) {
451 /*
452 * If we are using persistent grants and batch mappings only
453 * add the new maps to the list of persistent grants if the whole
454 * area can be persistently mapped.
455 */
456 if (batch_maps) {
457 region = g_malloc0(sizeof(*region));
458 region->addr = ioreq->pages;
459 region->num = new_maps;
460 ioreq->blkdev->persistent_regions = g_slist_append(
461 ioreq->blkdev->persistent_regions,
462 region);
463 }
464 while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
465 && new_maps) {
466 /* Go through the list of newly mapped grants and add as many
467 * as possible to the list of persistently mapped grants.
468 *
469 * Since we start at the end of ioreq->page(s), we only need
470 * to decrease new_maps to prevent this granted pages from
471 * being unmapped in ioreq_unmap.
472 */
473 grant = g_malloc0(sizeof(*grant));
474 new_maps--;
475 if (batch_maps) {
476 grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
477 } else {
478 grant->page = ioreq->page[new_maps];
479 }
480 grant->blkdev = ioreq->blkdev;
481 xen_pv_printf(&ioreq->blkdev->xendev, 3,
482 "adding grant %" PRIu32 " page: %p\n",
483 refs[new_maps], grant->page);
484 g_tree_insert(ioreq->blkdev->persistent_gnts,
485 GUINT_TO_POINTER(refs[new_maps]),
486 grant);
487 ioreq->blkdev->persistent_gnt_count++;
488 }
489 assert(!batch_maps || new_maps == 0);
490 }
491 for (i = 0; i < ioreq->v.niov; i++) {
492 ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
493 }
494 ioreq->mapped = 1;
495 ioreq->num_unmap = new_maps;
496 return 0;
497 }
498
499 #if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40800
500
501 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
502 {
503 int i;
504
505 for (i = 0; i < ioreq->v.niov; i++) {
506 ioreq->page[i] = NULL;
507 }
508
509 qemu_vfree(ioreq->pages);
510 }
511
512 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
513 {
514 int i;
515
516 if (ioreq->v.niov == 0) {
517 return 0;
518 }
519
520 ioreq->pages = qemu_memalign(XC_PAGE_SIZE, ioreq->v.niov * XC_PAGE_SIZE);
521
522 for (i = 0; i < ioreq->v.niov; i++) {
523 ioreq->page[i] = ioreq->pages + i * XC_PAGE_SIZE;
524 ioreq->v.iov[i].iov_base = ioreq->page[i];
525 }
526
527 return 0;
528 }
529
530 static int ioreq_grant_copy(struct ioreq *ioreq)
531 {
532 xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
533 xengnttab_grant_copy_segment_t segs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
534 int i, count, rc;
535 int64_t file_blk = ioreq->blkdev->file_blk;
536
537 if (ioreq->v.niov == 0) {
538 return 0;
539 }
540
541 count = ioreq->v.niov;
542
543 for (i = 0; i < count; i++) {
544 if (ioreq->req.operation == BLKIF_OP_READ) {
545 segs[i].flags = GNTCOPY_dest_gref;
546 segs[i].dest.foreign.ref = ioreq->refs[i];
547 segs[i].dest.foreign.domid = ioreq->domids[i];
548 segs[i].dest.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
549 segs[i].source.virt = ioreq->v.iov[i].iov_base;
550 } else {
551 segs[i].flags = GNTCOPY_source_gref;
552 segs[i].source.foreign.ref = ioreq->refs[i];
553 segs[i].source.foreign.domid = ioreq->domids[i];
554 segs[i].source.foreign.offset = ioreq->req.seg[i].first_sect * file_blk;
555 segs[i].dest.virt = ioreq->v.iov[i].iov_base;
556 }
557 segs[i].len = (ioreq->req.seg[i].last_sect
558 - ioreq->req.seg[i].first_sect + 1) * file_blk;
559 }
560
561 rc = xengnttab_grant_copy(gnt, count, segs);
562
563 if (rc) {
564 xen_pv_printf(&ioreq->blkdev->xendev, 0,
565 "failed to copy data %d\n", rc);
566 ioreq->aio_errors++;
567 return -1;
568 }
569
570 for (i = 0; i < count; i++) {
571 if (segs[i].status != GNTST_okay) {
572 xen_pv_printf(&ioreq->blkdev->xendev, 3,
573 "failed to copy data %d for gref %d, domid %d\n",
574 segs[i].status, ioreq->refs[i], ioreq->domids[i]);
575 ioreq->aio_errors++;
576 rc = -1;
577 }
578 }
579
580 return rc;
581 }
582 #else
583 static void ioreq_free_copy_buffers(struct ioreq *ioreq)
584 {
585 abort();
586 }
587
588 static int ioreq_init_copy_buffers(struct ioreq *ioreq)
589 {
590 abort();
591 }
592
593 static int ioreq_grant_copy(struct ioreq *ioreq)
594 {
595 abort();
596 }
597 #endif
598
599 static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
600
601 static void qemu_aio_complete(void *opaque, int ret)
602 {
603 struct ioreq *ioreq = opaque;
604 struct XenBlkDev *blkdev = ioreq->blkdev;
605
606 aio_context_acquire(blkdev->ctx);
607
608 if (ret != 0) {
609 xen_pv_printf(&blkdev->xendev, 0, "%s I/O error\n",
610 ioreq->req.operation == BLKIF_OP_READ ? "read" : "write");
611 ioreq->aio_errors++;
612 }
613
614 ioreq->aio_inflight--;
615 if (ioreq->presync) {
616 ioreq->presync = 0;
617 ioreq_runio_qemu_aio(ioreq);
618 goto done;
619 }
620 if (ioreq->aio_inflight > 0) {
621 goto done;
622 }
623
624 if (xen_feature_grant_copy) {
625 switch (ioreq->req.operation) {
626 case BLKIF_OP_READ:
627 /* in case of failure ioreq->aio_errors is increased */
628 if (ret == 0) {
629 ioreq_grant_copy(ioreq);
630 }
631 ioreq_free_copy_buffers(ioreq);
632 break;
633 case BLKIF_OP_WRITE:
634 case BLKIF_OP_FLUSH_DISKCACHE:
635 if (!ioreq->req.nr_segments) {
636 break;
637 }
638 ioreq_free_copy_buffers(ioreq);
639 break;
640 default:
641 break;
642 }
643 }
644
645 ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
646 if (!xen_feature_grant_copy) {
647 ioreq_unmap(ioreq);
648 }
649 ioreq_finish(ioreq);
650 switch (ioreq->req.operation) {
651 case BLKIF_OP_WRITE:
652 case BLKIF_OP_FLUSH_DISKCACHE:
653 if (!ioreq->req.nr_segments) {
654 break;
655 }
656 case BLKIF_OP_READ:
657 if (ioreq->status == BLKIF_RSP_OKAY) {
658 block_acct_done(blk_get_stats(blkdev->blk), &ioreq->acct);
659 } else {
660 block_acct_failed(blk_get_stats(blkdev->blk), &ioreq->acct);
661 }
662 break;
663 case BLKIF_OP_DISCARD:
664 default:
665 break;
666 }
667 qemu_bh_schedule(blkdev->bh);
668
669 done:
670 aio_context_release(blkdev->ctx);
671 }
672
673 static bool blk_split_discard(struct ioreq *ioreq, blkif_sector_t sector_number,
674 uint64_t nr_sectors)
675 {
676 struct XenBlkDev *blkdev = ioreq->blkdev;
677 int64_t byte_offset;
678 int byte_chunk;
679 uint64_t byte_remaining, limit;
680 uint64_t sec_start = sector_number;
681 uint64_t sec_count = nr_sectors;
682
683 /* Wrap around, or overflowing byte limit? */
684 if (sec_start + sec_count < sec_count ||
685 sec_start + sec_count > INT64_MAX >> BDRV_SECTOR_BITS) {
686 return false;
687 }
688
689 limit = BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS;
690 byte_offset = sec_start << BDRV_SECTOR_BITS;
691 byte_remaining = sec_count << BDRV_SECTOR_BITS;
692
693 do {
694 byte_chunk = byte_remaining > limit ? limit : byte_remaining;
695 ioreq->aio_inflight++;
696 blk_aio_pdiscard(blkdev->blk, byte_offset, byte_chunk,
697 qemu_aio_complete, ioreq);
698 byte_remaining -= byte_chunk;
699 byte_offset += byte_chunk;
700 } while (byte_remaining > 0);
701
702 return true;
703 }
704
705 static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
706 {
707 struct XenBlkDev *blkdev = ioreq->blkdev;
708
709 if (xen_feature_grant_copy) {
710 ioreq_init_copy_buffers(ioreq);
711 if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE ||
712 ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
713 ioreq_grant_copy(ioreq)) {
714 ioreq_free_copy_buffers(ioreq);
715 goto err;
716 }
717 } else {
718 if (ioreq->req.nr_segments && ioreq_map(ioreq)) {
719 goto err;
720 }
721 }
722
723 ioreq->aio_inflight++;
724 if (ioreq->presync) {
725 blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq);
726 return 0;
727 }
728
729 switch (ioreq->req.operation) {
730 case BLKIF_OP_READ:
731 block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
732 ioreq->v.size, BLOCK_ACCT_READ);
733 ioreq->aio_inflight++;
734 blk_aio_preadv(blkdev->blk, ioreq->start, &ioreq->v, 0,
735 qemu_aio_complete, ioreq);
736 break;
737 case BLKIF_OP_WRITE:
738 case BLKIF_OP_FLUSH_DISKCACHE:
739 if (!ioreq->req.nr_segments) {
740 break;
741 }
742
743 block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct,
744 ioreq->v.size,
745 ioreq->req.operation == BLKIF_OP_WRITE ?
746 BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH);
747 ioreq->aio_inflight++;
748 blk_aio_pwritev(blkdev->blk, ioreq->start, &ioreq->v, 0,
749 qemu_aio_complete, ioreq);
750 break;
751 case BLKIF_OP_DISCARD:
752 {
753 struct blkif_request_discard *req = (void *)&ioreq->req;
754 if (!blk_split_discard(ioreq, req->sector_number, req->nr_sectors)) {
755 goto err;
756 }
757 break;
758 }
759 default:
760 /* unknown operation (shouldn't happen -- parse catches this) */
761 if (!xen_feature_grant_copy) {
762 ioreq_unmap(ioreq);
763 }
764 goto err;
765 }
766
767 qemu_aio_complete(ioreq, 0);
768
769 return 0;
770
771 err:
772 ioreq_finish(ioreq);
773 ioreq->status = BLKIF_RSP_ERROR;
774 return -1;
775 }
776
777 static int blk_send_response_one(struct ioreq *ioreq)
778 {
779 struct XenBlkDev *blkdev = ioreq->blkdev;
780 int send_notify = 0;
781 int have_requests = 0;
782 blkif_response_t *resp;
783
784 /* Place on the response ring for the relevant domain. */
785 switch (blkdev->protocol) {
786 case BLKIF_PROTOCOL_NATIVE:
787 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.native,
788 blkdev->rings.native.rsp_prod_pvt);
789 break;
790 case BLKIF_PROTOCOL_X86_32:
791 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.x86_32_part,
792 blkdev->rings.x86_32_part.rsp_prod_pvt);
793 break;
794 case BLKIF_PROTOCOL_X86_64:
795 resp = (blkif_response_t *) RING_GET_RESPONSE(&blkdev->rings.x86_64_part,
796 blkdev->rings.x86_64_part.rsp_prod_pvt);
797 break;
798 default:
799 return 0;
800 }
801
802 resp->id = ioreq->req.id;
803 resp->operation = ioreq->req.operation;
804 resp->status = ioreq->status;
805
806 blkdev->rings.common.rsp_prod_pvt++;
807
808 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify);
809 if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) {
810 /*
811 * Tail check for pending requests. Allows frontend to avoid
812 * notifications if requests are already in flight (lower
813 * overheads and promotes batching).
814 */
815 RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests);
816 } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) {
817 have_requests = 1;
818 }
819
820 if (have_requests) {
821 blkdev->more_work++;
822 }
823 return send_notify;
824 }
825
826 /* walk finished list, send outstanding responses, free requests */
827 static void blk_send_response_all(struct XenBlkDev *blkdev)
828 {
829 struct ioreq *ioreq;
830 int send_notify = 0;
831
832 while (!QLIST_EMPTY(&blkdev->finished)) {
833 ioreq = QLIST_FIRST(&blkdev->finished);
834 send_notify += blk_send_response_one(ioreq);
835 ioreq_release(ioreq, true);
836 }
837 if (send_notify) {
838 xen_pv_send_notify(&blkdev->xendev);
839 }
840 }
841
842 static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc)
843 {
844 switch (blkdev->protocol) {
845 case BLKIF_PROTOCOL_NATIVE:
846 memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc),
847 sizeof(ioreq->req));
848 break;
849 case BLKIF_PROTOCOL_X86_32:
850 blkif_get_x86_32_req(&ioreq->req,
851 RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc));
852 break;
853 case BLKIF_PROTOCOL_X86_64:
854 blkif_get_x86_64_req(&ioreq->req,
855 RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc));
856 break;
857 }
858 /* Prevent the compiler from accessing the on-ring fields instead. */
859 barrier();
860 return 0;
861 }
862
863 static void blk_handle_requests(struct XenBlkDev *blkdev)
864 {
865 RING_IDX rc, rp;
866 struct ioreq *ioreq;
867
868 blkdev->more_work = 0;
869
870 rc = blkdev->rings.common.req_cons;
871 rp = blkdev->rings.common.sring->req_prod;
872 xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
873
874 blk_send_response_all(blkdev);
875 while (rc != rp) {
876 /* pull request from ring */
877 if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) {
878 break;
879 }
880 ioreq = ioreq_start(blkdev);
881 if (ioreq == NULL) {
882 blkdev->more_work++;
883 break;
884 }
885 blk_get_request(blkdev, ioreq, rc);
886 blkdev->rings.common.req_cons = ++rc;
887
888 /* parse them */
889 if (ioreq_parse(ioreq) != 0) {
890
891 switch (ioreq->req.operation) {
892 case BLKIF_OP_READ:
893 block_acct_invalid(blk_get_stats(blkdev->blk),
894 BLOCK_ACCT_READ);
895 break;
896 case BLKIF_OP_WRITE:
897 block_acct_invalid(blk_get_stats(blkdev->blk),
898 BLOCK_ACCT_WRITE);
899 break;
900 case BLKIF_OP_FLUSH_DISKCACHE:
901 block_acct_invalid(blk_get_stats(blkdev->blk),
902 BLOCK_ACCT_FLUSH);
903 default:
904 break;
905 };
906
907 if (blk_send_response_one(ioreq)) {
908 xen_pv_send_notify(&blkdev->xendev);
909 }
910 ioreq_release(ioreq, false);
911 continue;
912 }
913
914 ioreq_runio_qemu_aio(ioreq);
915 }
916
917 if (blkdev->more_work && blkdev->requests_inflight < blkdev->max_requests) {
918 qemu_bh_schedule(blkdev->bh);
919 }
920 }
921
922 /* ------------------------------------------------------------- */
923
924 static void blk_bh(void *opaque)
925 {
926 struct XenBlkDev *blkdev = opaque;
927
928 aio_context_acquire(blkdev->ctx);
929 blk_handle_requests(blkdev);
930 aio_context_release(blkdev->ctx);
931 }
932
933 static void blk_alloc(struct XenDevice *xendev)
934 {
935 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
936 Error *err = NULL;
937
938 trace_xen_disk_alloc(xendev->name);
939
940 QLIST_INIT(&blkdev->inflight);
941 QLIST_INIT(&blkdev->finished);
942 QLIST_INIT(&blkdev->freelist);
943
944 blkdev->iothread = iothread_create(xendev->name, &err);
945 assert(!err);
946
947 blkdev->ctx = iothread_get_aio_context(blkdev->iothread);
948 blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev);
949
950 if (xen_mode != XEN_EMULATE) {
951 batch_maps = 1;
952 }
953 }
954
955 static void blk_parse_discard(struct XenBlkDev *blkdev)
956 {
957 int enable;
958
959 blkdev->feature_discard = true;
960
961 if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) {
962 blkdev->feature_discard = !!enable;
963 }
964
965 if (blkdev->feature_discard) {
966 xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1);
967 }
968 }
969
970 static int blk_init(struct XenDevice *xendev)
971 {
972 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
973 int info = 0;
974 char *directiosafe = NULL;
975
976 trace_xen_disk_init(xendev->name);
977
978 /* read xenstore entries */
979 if (blkdev->params == NULL) {
980 char *h = NULL;
981 blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
982 if (blkdev->params != NULL) {
983 h = strchr(blkdev->params, ':');
984 }
985 if (h != NULL) {
986 blkdev->fileproto = blkdev->params;
987 blkdev->filename = h+1;
988 *h = 0;
989 } else {
990 blkdev->fileproto = "<unset>";
991 blkdev->filename = blkdev->params;
992 }
993 }
994 if (!strcmp("aio", blkdev->fileproto)) {
995 blkdev->fileproto = "raw";
996 }
997 if (!strcmp("vhd", blkdev->fileproto)) {
998 blkdev->fileproto = "vpc";
999 }
1000 if (blkdev->mode == NULL) {
1001 blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode");
1002 }
1003 if (blkdev->type == NULL) {
1004 blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type");
1005 }
1006 if (blkdev->dev == NULL) {
1007 blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev");
1008 }
1009 if (blkdev->devtype == NULL) {
1010 blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type");
1011 }
1012 directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe");
1013 blkdev->directiosafe = (directiosafe && atoi(directiosafe));
1014
1015 /* do we have all we need? */
1016 if (blkdev->params == NULL ||
1017 blkdev->mode == NULL ||
1018 blkdev->type == NULL ||
1019 blkdev->dev == NULL) {
1020 goto out_error;
1021 }
1022
1023 /* read-only ? */
1024 if (strcmp(blkdev->mode, "w")) {
1025 info |= VDISK_READONLY;
1026 }
1027
1028 /* cdrom ? */
1029 if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) {
1030 info |= VDISK_CDROM;
1031 }
1032
1033 blkdev->file_blk = BLOCK_SIZE;
1034
1035 xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",
1036 xen_feature_grant_copy ? "enabled" : "disabled");
1037
1038 /* fill info
1039 * blk_connect supplies sector-size and sectors
1040 */
1041 xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
1042 xenstore_write_be_int(&blkdev->xendev, "feature-persistent",
1043 !xen_feature_grant_copy);
1044 xenstore_write_be_int(&blkdev->xendev, "info", info);
1045
1046 xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order",
1047 MAX_RING_PAGE_ORDER);
1048
1049 blk_parse_discard(blkdev);
1050
1051 g_free(directiosafe);
1052 return 0;
1053
1054 out_error:
1055 g_free(blkdev->params);
1056 blkdev->params = NULL;
1057 g_free(blkdev->mode);
1058 blkdev->mode = NULL;
1059 g_free(blkdev->type);
1060 blkdev->type = NULL;
1061 g_free(blkdev->dev);
1062 blkdev->dev = NULL;
1063 g_free(blkdev->devtype);
1064 blkdev->devtype = NULL;
1065 g_free(directiosafe);
1066 blkdev->directiosafe = false;
1067 return -1;
1068 }
1069
1070 /*
1071 * We need to account for the grant allocations requiring contiguous
1072 * chunks; the worst case number would be
1073 * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
1074 * but in order to keep things simple just use
1075 * 2 * max_req * max_seg.
1076 */
1077 #define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
1078
1079 static int blk_connect(struct XenDevice *xendev)
1080 {
1081 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1082 int pers, index, qflags;
1083 bool readonly = true;
1084 bool writethrough = true;
1085 int order, ring_ref;
1086 unsigned int ring_size, max_grants;
1087 unsigned int i;
1088 uint32_t *domids;
1089
1090 trace_xen_disk_connect(xendev->name);
1091
1092 /* read-only ? */
1093 if (blkdev->directiosafe) {
1094 qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
1095 } else {
1096 qflags = 0;
1097 writethrough = false;
1098 }
1099 if (strcmp(blkdev->mode, "w") == 0) {
1100 qflags |= BDRV_O_RDWR;
1101 readonly = false;
1102 }
1103 if (blkdev->feature_discard) {
1104 qflags |= BDRV_O_UNMAP;
1105 }
1106
1107 /* init qemu block driver */
1108 index = (blkdev->xendev.dev - 202 * 256) / 16;
1109 blkdev->dinfo = drive_get(IF_XEN, 0, index);
1110 if (!blkdev->dinfo) {
1111 Error *local_err = NULL;
1112 QDict *options = NULL;
1113
1114 if (strcmp(blkdev->fileproto, "<unset>")) {
1115 options = qdict_new();
1116 qdict_put_str(options, "driver", blkdev->fileproto);
1117 }
1118
1119 /* setup via xenbus -> create new block driver instance */
1120 xen_pv_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
1121 blkdev->blk = blk_new_open(blkdev->filename, NULL, options,
1122 qflags, &local_err);
1123 if (!blkdev->blk) {
1124 xen_pv_printf(&blkdev->xendev, 0, "error: %s\n",
1125 error_get_pretty(local_err));
1126 error_free(local_err);
1127 return -1;
1128 }
1129 blk_set_enable_write_cache(blkdev->blk, !writethrough);
1130 } else {
1131 /* setup via qemu cmdline -> already setup for us */
1132 xen_pv_printf(&blkdev->xendev, 2,
1133 "get configured bdrv (cmdline setup)\n");
1134 blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo);
1135 if (blk_is_read_only(blkdev->blk) && !readonly) {
1136 xen_pv_printf(&blkdev->xendev, 0, "Unexpected read-only drive");
1137 blkdev->blk = NULL;
1138 return -1;
1139 }
1140 /* blkdev->blk is not create by us, we get a reference
1141 * so we can blk_unref() unconditionally */
1142 blk_ref(blkdev->blk);
1143 }
1144 blk_attach_dev_legacy(blkdev->blk, blkdev);
1145 blkdev->file_size = blk_getlength(blkdev->blk);
1146 if (blkdev->file_size < 0) {
1147 BlockDriverState *bs = blk_bs(blkdev->blk);
1148 const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL;
1149 xen_pv_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n",
1150 (int)blkdev->file_size, strerror(-blkdev->file_size),
1151 drv_name ?: "-");
1152 blkdev->file_size = 0;
1153 }
1154
1155 xen_pv_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\","
1156 " size %" PRId64 " (%" PRId64 " MB)\n",
1157 blkdev->type, blkdev->fileproto, blkdev->filename,
1158 blkdev->file_size, blkdev->file_size >> 20);
1159
1160 /* Fill in number of sector size and number of sectors */
1161 xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk);
1162 xenstore_write_be_int64(&blkdev->xendev, "sectors",
1163 blkdev->file_size / blkdev->file_blk);
1164
1165 if (xenstore_read_fe_int(&blkdev->xendev, "ring-page-order",
1166 &order) == -1) {
1167 blkdev->nr_ring_ref = 1;
1168
1169 if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref",
1170 &ring_ref) == -1) {
1171 return -1;
1172 }
1173 blkdev->ring_ref[0] = ring_ref;
1174
1175 } else if (order >= 0 && order <= MAX_RING_PAGE_ORDER) {
1176 blkdev->nr_ring_ref = 1 << order;
1177
1178 for (i = 0; i < blkdev->nr_ring_ref; i++) {
1179 char *key;
1180
1181 key = g_strdup_printf("ring-ref%u", i);
1182 if (!key) {
1183 return -1;
1184 }
1185
1186 if (xenstore_read_fe_int(&blkdev->xendev, key,
1187 &ring_ref) == -1) {
1188 g_free(key);
1189 return -1;
1190 }
1191 blkdev->ring_ref[i] = ring_ref;
1192
1193 g_free(key);
1194 }
1195 } else {
1196 xen_pv_printf(xendev, 0, "invalid ring-page-order: %d\n",
1197 order);
1198 return -1;
1199 }
1200
1201 if (xenstore_read_fe_int(&blkdev->xendev, "event-channel",
1202 &blkdev->xendev.remote_port) == -1) {
1203 return -1;
1204 }
1205 if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
1206 blkdev->feature_persistent = FALSE;
1207 } else {
1208 blkdev->feature_persistent = !!pers;
1209 }
1210
1211 if (!blkdev->xendev.protocol) {
1212 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1213 } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
1214 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1215 } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
1216 blkdev->protocol = BLKIF_PROTOCOL_X86_32;
1217 } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
1218 blkdev->protocol = BLKIF_PROTOCOL_X86_64;
1219 } else {
1220 blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
1221 }
1222
1223 ring_size = XC_PAGE_SIZE * blkdev->nr_ring_ref;
1224 switch (blkdev->protocol) {
1225 case BLKIF_PROTOCOL_NATIVE:
1226 {
1227 blkdev->max_requests = __CONST_RING_SIZE(blkif, ring_size);
1228 break;
1229 }
1230 case BLKIF_PROTOCOL_X86_32:
1231 {
1232 blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_32, ring_size);
1233 break;
1234 }
1235 case BLKIF_PROTOCOL_X86_64:
1236 {
1237 blkdev->max_requests = __CONST_RING_SIZE(blkif_x86_64, ring_size);
1238 break;
1239 }
1240 default:
1241 return -1;
1242 }
1243
1244 /* Calculate the maximum number of grants needed by ioreqs */
1245 max_grants = MAX_GRANTS(blkdev->max_requests,
1246 BLKIF_MAX_SEGMENTS_PER_REQUEST);
1247 /* Add on the number needed for the ring pages */
1248 max_grants += blkdev->nr_ring_ref;
1249
1250 blkdev->xendev.gnttabdev = xengnttab_open(NULL, 0);
1251 if (blkdev->xendev.gnttabdev == NULL) {
1252 xen_pv_printf(xendev, 0, "xengnttab_open failed: %s\n",
1253 strerror(errno));
1254 return -1;
1255 }
1256 if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, max_grants)) {
1257 xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
1258 strerror(errno));
1259 return -1;
1260 }
1261
1262 domids = g_new0(uint32_t, blkdev->nr_ring_ref);
1263 for (i = 0; i < blkdev->nr_ring_ref; i++) {
1264 domids[i] = blkdev->xendev.dom;
1265 }
1266
1267 blkdev->sring = xengnttab_map_grant_refs(blkdev->xendev.gnttabdev,
1268 blkdev->nr_ring_ref,
1269 domids,
1270 blkdev->ring_ref,
1271 PROT_READ | PROT_WRITE);
1272
1273 g_free(domids);
1274
1275 if (!blkdev->sring) {
1276 return -1;
1277 }
1278
1279 blkdev->cnt_map++;
1280
1281 switch (blkdev->protocol) {
1282 case BLKIF_PROTOCOL_NATIVE:
1283 {
1284 blkif_sring_t *sring_native = blkdev->sring;
1285 BACK_RING_INIT(&blkdev->rings.native, sring_native, ring_size);
1286 break;
1287 }
1288 case BLKIF_PROTOCOL_X86_32:
1289 {
1290 blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring;
1291
1292 BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, ring_size);
1293 break;
1294 }
1295 case BLKIF_PROTOCOL_X86_64:
1296 {
1297 blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring;
1298
1299 BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, ring_size);
1300 break;
1301 }
1302 }
1303
1304 if (blkdev->feature_persistent) {
1305 /* Init persistent grants */
1306 blkdev->max_grants = blkdev->max_requests *
1307 BLKIF_MAX_SEGMENTS_PER_REQUEST;
1308 blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
1309 NULL, NULL,
1310 batch_maps ?
1311 (GDestroyNotify)g_free :
1312 (GDestroyNotify)destroy_grant);
1313 blkdev->persistent_regions = NULL;
1314 blkdev->persistent_gnt_count = 0;
1315 }
1316
1317 blk_set_aio_context(blkdev->blk, blkdev->ctx);
1318
1319 xen_be_bind_evtchn(&blkdev->xendev);
1320
1321 xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, nr-ring-ref %u, "
1322 "remote port %d, local port %d\n",
1323 blkdev->xendev.protocol, blkdev->nr_ring_ref,
1324 blkdev->xendev.remote_port, blkdev->xendev.local_port);
1325 return 0;
1326 }
1327
1328 static void blk_disconnect(struct XenDevice *xendev)
1329 {
1330 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1331
1332 trace_xen_disk_disconnect(xendev->name);
1333
1334 aio_context_acquire(blkdev->ctx);
1335
1336 if (blkdev->blk) {
1337 blk_set_aio_context(blkdev->blk, qemu_get_aio_context());
1338 blk_detach_dev(blkdev->blk, blkdev);
1339 blk_unref(blkdev->blk);
1340 blkdev->blk = NULL;
1341 }
1342 xen_pv_unbind_evtchn(&blkdev->xendev);
1343
1344 aio_context_release(blkdev->ctx);
1345
1346 if (blkdev->sring) {
1347 xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring,
1348 blkdev->nr_ring_ref);
1349 blkdev->cnt_map--;
1350 blkdev->sring = NULL;
1351 }
1352
1353 /*
1354 * Unmap persistent grants before switching to the closed state
1355 * so the frontend can free them.
1356 *
1357 * In the !batch_maps case g_tree_destroy will take care of unmapping
1358 * the grant, but in the batch_maps case we need to iterate over every
1359 * region in persistent_regions and unmap it.
1360 */
1361 if (blkdev->feature_persistent) {
1362 g_tree_destroy(blkdev->persistent_gnts);
1363 assert(batch_maps || blkdev->persistent_gnt_count == 0);
1364 if (batch_maps) {
1365 blkdev->persistent_gnt_count = 0;
1366 g_slist_foreach(blkdev->persistent_regions,
1367 (GFunc)remove_persistent_region, blkdev);
1368 g_slist_free(blkdev->persistent_regions);
1369 }
1370 blkdev->feature_persistent = false;
1371 }
1372
1373 if (blkdev->xendev.gnttabdev) {
1374 xengnttab_close(blkdev->xendev.gnttabdev);
1375 blkdev->xendev.gnttabdev = NULL;
1376 }
1377 }
1378
1379 static int blk_free(struct XenDevice *xendev)
1380 {
1381 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1382 struct ioreq *ioreq;
1383
1384 trace_xen_disk_free(xendev->name);
1385
1386 blk_disconnect(xendev);
1387
1388 while (!QLIST_EMPTY(&blkdev->freelist)) {
1389 ioreq = QLIST_FIRST(&blkdev->freelist);
1390 QLIST_REMOVE(ioreq, list);
1391 qemu_iovec_destroy(&ioreq->v);
1392 g_free(ioreq);
1393 }
1394
1395 g_free(blkdev->params);
1396 g_free(blkdev->mode);
1397 g_free(blkdev->type);
1398 g_free(blkdev->dev);
1399 g_free(blkdev->devtype);
1400 qemu_bh_delete(blkdev->bh);
1401 iothread_destroy(blkdev->iothread);
1402 return 0;
1403 }
1404
1405 static void blk_event(struct XenDevice *xendev)
1406 {
1407 struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
1408
1409 qemu_bh_schedule(blkdev->bh);
1410 }
1411
1412 struct XenDevOps xen_blkdev_ops = {
1413 .size = sizeof(struct XenBlkDev),
1414 .alloc = blk_alloc,
1415 .init = blk_init,
1416 .initialise = blk_connect,
1417 .disconnect = blk_disconnect,
1418 .event = blk_event,
1419 .free = blk_free,
1420 };
QEmu